Isolation Mode
Isolation mode allows to list new assets as Isolated which has a specific debt ceiling and can be only used to borrow stablecoins that have been permitted, by Aave Governance, to be borrowable in isolation mode.
Debt Ceiling for an *Isolated Asset* is represented as the maximum amount in USD that can be borrowed against the collateral with two decimals of precision.

Supply Isolated Asset

A user can supply an Isolated Asset just like any other asset using supply() method in pool.sol, though, the default behaviour while supplying an Isolated Asset may vary based on below conditions
Use as Collateral
Condition
Enabled
- if Isolated Asset is the first asset supplied by the user OR - no other supplied asset is enabled as collateral by the user
Disabled
if any other asset is currently enabled as collateral
In case the user has other assets enabled as collateral, they can still supply Isolated Asset to capture the yield but won’t be able to use it as collateral

Borrow in Isolated Mode

Borrowers using an Isolated Asset as collateral can only use that particular asset as collateral and can only borrow assets that are borrowable in isolation mode, i.e. have BORROWABLE_IN_ISOLATION_MASK bit set in reserve configuration.
Borrower in Isolation Mode cannot enable any other assets including the other isolated assets as collateral.

Exit Isolation Mode

Users can turn off isolation mode by disabling the isolated asset as collateral. This can be done only if the user has no outstanding debt. A user must use repay() method in Pool.sol to pay off all of their debt before exiting Isolation Mode